This invention relates to a radiation apparatus for cosmetic, photobiological and/or photochemical purposes containing at least one ultraviolet ray source and devices for producing the ignition voltage and the operating current necessary for the operation and preferably including a filter apparatus.
The radiation apparatus is to serve for the treatment of different diseases, for example, psoriasis, hyperbilirubinamie. Furthermore it is to be used for cosmetic purposes for direct tanning.
Also it is used in the field of photo chemistry, for example, for drying of varnishes, for the hardening of plastic and for polymerization.
At present it is known to use in the field of photobiology for medicinal as well as for cosmetic purposes, radiation apparatus with electric ultraviolet ray sources for treatment of different diseases (for example, psoriasis, hyperbilirubinamie) by ultraviolet radiations used in conjunction with medicines. In psoriasis treatment with ultraviolet fluorescent lamps, in which radiation strengths of about 60 W/m.sup.2 are used (with 365 nm), there is a psychological disadvantage to the patient because he must be practically shut up in a box. For cosmetic purposes especially in order to achieve the effect of secondary pigmentation (tanning after previous erythema) ultraviolet radiation with a wave length shorter than 320 nm is used.
Furthermore it is known that in solaria light sources of the aforementioned type are used.
As a rule for photochemical purposes, for the drying of varnishes, for the hardening of plastics and for polymerization mercury vapor high pressure lamps are used which emit mixed light in the region of about 250 nm up to, for the tube radiation, several 1000 nm.
Instead of mercury, high or low pressure lamps, the latter for most part with fluorescence, and xenon high pressure lamps are used in such fields. The presently known radiation devices emit to a not inconsiderable extent conjunctivitis- and erythema-active rays, which in wrong dosages, can bring about considerable damage to health. This applies above all to ultraviolet ray sources which operate in the high pressure range. Radiation devices for photobiological purposes equipped with low pressure mercury vapor lamps (fluorescent lamps) are extremely expensive so that they can be used only in clinics and large practices and not for home treatment.
The object of the invention is to provide a radiation apparatus for photobiological and photochemical purposes which supplies in the wave length region of 320-450 nm high radiation strengths and completely suppresses the radiation wave length shorter than 320 nm in order to avoid damage to health by conjunctivitis (inflammation of the conjunctiva) and erythema (sunburn). Furthermore radiation of longer wave length than 450 nm should be substantially suppressed in order to avoid undesired effects on the radiation objects due to high energy loading. To be avoided in particular are dazzling, and damage to the skin by too high radiation loads, the latter particularly in the infra red range.
This problem is solved according to the invention in that the short wave rays below 320 nm are completely suppressed. Discharge lamps which usually are used as ultraviolet ray sources emit the greatest part of their energy in the infra red range. Therefore the infra red rays as of about 800 nm are suppressed as far as possible. In order to reduce the radiation outside the effective range which is between 320 and about 450 nm it is desirable to filter out substantially all the longer wave rays above 450 nm.
An ultraviolet ray source of especially high intensity in the region of 320-450 nm is the mercury vapor high pressure lamps especially those provided with iron iodide and gallium iodide.
In order to obviate the devices connected in series usually necessary for the operation of the mercury vapor high pressure lamp, the lamp may be constructed as a mixed light lamp with the current limitation effected by an incandescent lamp winding.
An ultraviolet ray source which operates as a high or maximum xenon pressure lamp can be intensified in the region of 320-450 nm if it is provided with a metal iodide, preferably iron iodide and gallium iodide.
The short wave rays under 320 nm are suppressed by an ultraviolet edge filter. A very simple ultraviolet edge filter can be produced from plate glass and is usual in the art.
If the temperatures are not too high polyesters also can be used as ultraviolet filters, either in the form of plates or foils. Applying polyester foil directly on the bulb or tube of the fluorescent lamp insures that no rays under 320 nm emerge.
The radiation load in the visible range above 450 nm can be achieved by the use of color filters, preferably a blue violet filter. This filter may consist of glass, quartz or plastics in which finely divided heavy metal oxides, for example, cobalt, nickel, iron-oxide are dispersed or deposited on the surface.
A color filter made from the violet glass may be placed over the burner of the high pressure lamp. It also serves as a protective tube for the sensitive burner quartz tube. If cobalt oxide is added to the fused quartz, the burner tube itself may serve as a blue violet filter whereby with suitable proportioning of the amount added, ultraviolet filtering in the region below 320 nm can be achieved.
In the radiation procedure an infra red filter may be inserted between the ultraviolet ray source and the radiation object which may act either as an absorption or reflection filter.
The simplest solution of this type is to use a heat absorptive glass, usual in the art, as an infra red filter. Instead of the maximum necessary three filter types, a single filter may fulfill the three functions if, for example, the corresponding additional materials for the color filtering and/or infra red filtering are added to the plate glass fusion in suitable quantities. The same applies if instead of the plate glass fusion a quartz fusion is used or the filter materials are finely divided in plastics or deposited on the surface.
The housing in which the ultraviolet ray source is located is produced either from polished oxidized aluminum or it contains reflectors from this material in order to increase the radiation output.
For cooling of the housing ventilation openings with shield plates are provided so that no unfiltered rays can emerge from the housing. The arrangement of these inlet and outlet openings is such that the ray source, the housing and the filters are sufficiently cooled.
For increasing the cooling effect a ventilator is provided in order to carry out the cooling more effectively.
The cooling of ultraviolet ray source and/or housing is suitably regulable or adjustable. This gives an optimum operating temperature for the housing and lamp. The housing must not be too hot because of the added devices and the danger of burns to operator of the radiation apparatus.
The cooling may be effected by means of a ventilator and/or a blower, regulated or adjusted by electrical means.
Advantageously the cooling is controlled so that the ultraviolet ray source is not cooled during ignition. Thus, an optimum operating temperature of the burner results; if the space between the burner and the protective tube upon starting the lamp is completely cooled, the optimum operating temperature of the burner is not obtained.
The cooling is suitably regulated by an electronic delay switch which preferably also monitors the temperature of the ultraviolet ray source and/or housing.
In order to obtain as high an ultraviolet ray output as possible the temperature at the wall of the burner must not fall short of a certain minimum value. On the other hand, it is important that at the place where the current leads to the electrode are embedded a maximum temperature must not be exceeded if the lamp is not to burn out prematurely.
The exhaust cooling air may be discharged outside the room.
Radiation devices of extremely high outputs containing several ultraviolet ray sources will heat up the room excessively if the exhaust air from cooling remains in the room.
At least one additional ultra violet ray source which emits erythema-effective rays is included. It may be operated continuously or intermittently by impulse switching.
Advantageously the ignition device is switched off after the ignition of the ultraviolet ray source.
The ignition, which requires higher voltages than the usual line voltages, is effected either by resonance switchings, transformers or high frequency ignition devices which consist of spark sections and windings. After ignition with a high frequency device the full lamp current flows through the windings. Therefore the windings must be dimensioned correspondingly thick. If the ignition device is switched off after the ignition of the ultraviolet ray source considerable saving in cost, weight and space can be achieved.
The current drawn by the radiation device is of such magnitude that current plugs used for normal domestic current circuits will suffice. Thus the radiation apparatus can be used as a home radiation apparatus.
Also in order to be able to carry out home radiations it is necessary to design the electrical parts of the radiation apparatus so that they will operate on standard house voltage and current. This means that the lamp-burning voltage must amount to a maximum of 2/3 the line voltage of the power supply and must be properly fused so as not to exceed the maximum line current. On the other hand the highest possible output of the ultraviolet ray source (lamp) is necessary in order to achieve the best possible effect in the shortest time.
The space between the burner bulb and protective tube may be cooled by air preferably supplied from the previously-described ventilator. The air cooling if necessary may be supplemented or replaced by suitably-arranged water cooling. Care must be taken that liquid coolant does not contact the burner, since a mercury vapor high pressure lamp for example operates at a temperature between 700.degree. and 900.degree. C.
Special advantages of the radiation apparatus of the invention are:
Avoiding of conjunctivitis and erythema by the filtering out of the rays below 320 nm, which rays according to the literature have a carcinogenic effect.
By filtering out the infra red radiation the heat loading of the radiation object is considerably reduced so that even with very intensive radiation no heat erythema results. With a pigmenting effective radiation strength of about 150 W/m.sup.2, a total radiation loading of about 2500 W/m.sup.2 would result if the infra red and visible-light portions are not filtered out. If these wave lengths are filtered out this value is reduced by about 80%.
Due to the blue violet filter the luminous density of the light source is reduced so markedly that any permanent dazzle phenomena is eliminated.
The use of gallium iodide and iron iodide increases the radiation output of the high pressure discharge in the range of 320-450 nm by a considerable amount. If the mercury vapor high pressure lamp is constructed as a mixed light lamp the added device is dispensable and the lamp can be operated directly on standard power supply.
Ultraviolet edge filters made from plate glass known in the art are extraordinarily cheap. The same applies to filters from polyesters. If a blue violet glass tube is used as the color filter, this results in a considerable reduction in cost compared with blue violet filter discs.
One of the most important advantages however is that radiation wave lengths between 320 nm and 450 nm can now be achieved cheaply in practice. This applies to photobiology as well as also to photo chemistry.